1. Field of the Invention
This invention relates generally to improvements in tilting check valves and, more particularly, but not by way of limitation, to improvements facilitating rapid and inexpensive repair of valves which have become worn in use.
2. Discussion of the Prior Art
In many industrial processes, it is necessary to provide for unidirectional flow through a number of conduits which transport fluids about plants wherein the processes are carried out. When the conduits are of relatively large diameter, it is common to use a check valve of the tilting disc type for this purpose. Such valves generally provide dependable service at reasonable cost and are, accordingly, in widespread use. A tilting disc check valve generally comprises a clapper pivotally mounted within the body of the valve to pivot toward or away from an annular seat. Fluid flow from one side of the clapper forces the clapper away from the seat to permit passage of the fluid through the valve while backflow is prevented by pivotation of the clapper against the seat. Examples of such construction are found in the applicant's U.S. Pat. No. 3,491,796, issued Jan. 27, 1970, and in U.S. Pat. No. 3,934,608, issued Jan. 27, 1976 to Guyton.
While tilting disc check valves have proven themselves to be useful and dependable devices, they are, as is the case with any type of valve, subject to wear so that valves must be periodically repaired. It is known to accomplish repair by replacing a valve assembly which forms a distinct component of the valve and is mounted in a valve body which can be removed temporarily from a conduit or which can be disassembled. Examples of valves including replaceable valve assemblies are the valves disclosed in U.S. Pat. No. 4,128,111, issued Dec. 5, 1978 to Hansen et al. and in U.S. Pat. No. 286,676, issued Oct. 16, 1883 to Belknap et al.